In this study, wear behavior of biodegradable Mg–5Zn–1Y–(0–1)Ca alloys is investigated in simulated body fluid. Weartest is performed using a pin-on-disc system, under three different loads of 10, 20 and 40 N, at ambient temperature; andthe whole configuration is exposed to simulated body fluid. The volumetric wear rate and friction coefficient of each alloyare determined. The worn surfaces are analyzed using a scanning electron microscope, equipped with an energy dispersivespectrometer to determine the involved main wear mechanism. The Ca-free alloy contains α-Mg and intermetallic Mg3YZn6,and Ca addition produces another intermetallic Ca2Mg6Zn3. Results show that different wear mechanisms and rates, as wellas friction coefficients, are achieved due to the effect of simulated body fluid on the alloys with regards to the different Cacontent and the presence of corrosion products. Microscopic studies reveal that abrasion is the dominant wear mechanismtaken place in all alloys under all loads. Increasing Ca content leads to wear resistance deterioration while increasing wearload results in decreasing wear rate and friction coefficient of the alloys. The results of the wear rate and friction coefficientof Mg–5Zn–1Y–1Ca alloy exhibit greater instability compared to the other alloys due to its more enhanced corrosion causedby the formation of the intermetallic Ca2Mg6Zn3particles. In total, Ca-free alloy provides the best wear resistance, especiallyat the higher wear load.